- In a 1-litre three-necked flask, provided with a dropping funnel, a sealed stirrer and a reflux condenser, place 14.4g (0.1 mol) of 2-naphthol and 600 ml of water, and heat to the boiling point.
- To the boiling liquid containing liquid 2-naphthol in suspension, add slowly through the dropping funnel and with vigorous stirring a solution of 28 g (0.1 mol) of crystallised iron(m) chloride in 60 ml of water.
- The oily drops of 2-naphthol will disappear and the bis-2-naphthol separates out in flakes.
- Boil for 5-10 minutes, filter the hot suspension at the pump through a previously warmed Buchner funnel, wash with boiling water and dry in the air upon filter paper.
- The crude product weighs 9g.
- Recrystallise from toluene (about 150 ml); almost colourless crystals (7.5g, 52%), m.p. 218 °C, are obtained.
